Knowledge Check

One-time listener

Which listener option removes the listener automatically after its first invocation?

What this task practices

One-time listener is a knowledge check interview exercise that trains prompt interpretation, explicit assumptions, a concrete response, and a clear explanation of tradeoffs. The catalog marks it as medium difficulty. It focuses on Frontend Language Browser, Dom Events. The signed-in workspace provides the tools for the round and evaluates the attempt against task-specific criteria. Reference solutions, hidden checks, evaluator instructions, and candidate work remain private.